The present invention generally relates to machines for binding together stacks of perforated paper sheets, and more particularly, relates to a binding apparatus for forming a wire binder.
Books, papers and documents are often bound by a wire comb binder which includes a row of ringlets. Initially, the ringlets have open ends to permit the insertion of perforated pages onto the binder. By use of a binding apparatus, the wire comb binder is squeezed, plastically deforming to close the ringlets. Various binding machines are known for formably closing the binder. For example, U.K. Patent Application GB 2 327 204 A, which claims priority on GB 9712718, incorporated herein by reference, discloses a binding apparatus in which first and second, planar, opposed forming surfaces for closing a wire binder therebetween. The binding apparatus has a plurality of hooks to hold the wire comb binder between the two opposed forming surfaces. Initially, the wire comb binder is hung from the hooks in an open condition so that the open ringlets of the wire comb binder are positioned to receive a stack of perforated sheets. The opposed pair of forming surfaces are then moved toward each other, squeezing the binder to close the wire ringlets.
Various problems exist with such known binding mechanisms. For example, the wire ringlets can become misaligned because free ends of the wire binder are unguided during the operation of deflectably closing the wire ringlets.
Other known binding systems required a two-stage process wherein the perforated sheets are inserted onto binder ringlets at a first stage, then the binder is moved to a second stage for a closing operation. This two-stage process is inconvenient as well as time consuming.
The present invention provides an improved binding apparatus for forming a wire binder. In an embodiment, the binding apparatus has a base and a pivotable former door movable between open and closed positions. The apparatus has three forming surfaces or former bars, including parallel, opposed first and second former bars, as well as an adjacently-positioned third former bar oriented generally perpendicularly to the first and second former bars. For the purposes of this disclosure, the terms xe2x80x9cformer barxe2x80x9d and xe2x80x9cformer surfacexe2x80x9d are used interchangeably. Generally, the apparatus is operable to squeeze a wire binder between the opposed first and second forming bars to close the wire ringlets, as a spine ends and free ends of the wire ringlets guidably slide against the perpendicular third former bar.
Advantageously, the invention provides a binding apparatus configuration which facilitates loading of the open binder at the same place at which the closing operation occurs. Particularly, in the preferred embodiment, the second and third former bars are mounted to a pivotably mounted former door. For convenient loading of the wire binder and sheets without interference by the second and third former bars, the former door is pivoted to the open position. When the door is open, a plurality of hooks is accessible for initially supporting the wire binder in a held position. The hooks are mounted to the base of the binding apparatus adjacently above the first former bar so that the binder is supported against the adjacent first former bar while hanging from the hooks. The wire binder (in an xe2x80x9copenxe2x80x9d condition) is hung on the hooks, positioning the free ends of the ringlets to receive a stack of perforated sheets.
When the wire binder has been loaded with a desired stack of sheets to be bound, the door is moved to a closed position, positioning the wire binder within a space between the first and second former bars with the free ends of the wire binder in contact against the third former bar. From this position, the first and second former bars are movable relative to each other to squeeze the binder closed. The third former surface or bar of the binding apparatus according to the present invention serves to guide the ends of each wire ringlet during the squeezing of the wire binder between the first and second former bars. This causes the wire binder to plastically close such that the proximal and distal ends of each ringlet reliably meet.
In a first embodiment, the first former bar is movably mounted relative to the base on a cam-actuated slider mechanism. This bends the wire binder to a xe2x80x9cclosedxe2x80x9d condition, the spine ends and free ends of the wire ringlets guidably sliding along the third former bar. In an embodiment, the second and third former bars remain fixed during the closing motion of the first former bar. Alternate embodiments are also possible wherein the second former bar is movable toward the first former bar during the closing operation. For example, the binding apparatus may include a linkage for driving both the first and second former bars toward each other.
An advantage of the present invention is that it is, at least partially, self-adjusting, avoiding a need to adjust the orientation of the wire binder element as is required in some known binding machines. More particularly, as the door is closed, the third former bar contacts the wire binder element and causes it to xe2x80x9crollxe2x80x9d along the first former bar until the door is fully closed. At this point, both the spine ends and free ends of the wire ringlets contact the third former bar, optimally positioning the binder element for the closing operation. This advantageously avoids a need to adjust the hooks of a known binding machine in order to properly position the wire binder element between former bars for closing.
For adjusting the binding apparatus to accommodate wire binders of different sizes, in an embodiment, the pivot point of the door is linearly adjustable. More specifically, the door hinges on a pair of pivots which reside in respective slots. An adjusting mechanism positions the door at a selected position. In the embodiment wherein the second and third former bars are fixedly mounted to the door and the first former bar is movably mounted to the base, the present invention provides a simple and efficient assembly of components. Specifically, the movable-door arrangement permits the movable first former to be operated by a simple mechanism, such as a cam mechanism, which displaces the first former bar by a predetermined distance regardless of binder size. The adjustable position of the door permits a full range of adjustability for closing different sized binders with the displaceable first former bar.
In accordance with teachings of the invention, the hooks are preferably movable against a spring bias, allowing the hooks to pivot under the weight of the stack of sheets received thereon and to accommodate the motion of the wire binder when the closure door is moved to the closed position against the wire binder. More specifically, when the door is closed, the hooks urge the wire binder element so that the spine ends and free ends of the wire binder lie against the third closure bar in proper alignment for squeezing between the first and second former bars. A locking mechanism may optionally be provided to lock the hooks into a predetermined position while the door is open. Closing the door actuates a release of the locking mechanism to release the hooks. This locking feature advantageously holds the hooks for convenient loading of paper sheets, then permits biased movement of the binder to maintain proper orientation during the closing of the former bars. For example, the locking mechanism may include a magnet mounted to the sliding plate on which the hooks are mounted, magnetically holding the plate in the predetermined position until the magnetic force is overcome. Alternatively, the locking mechanism may include a physical latching structure, such as an movable pin, that mechanically engages to hold the pins in the predetermined position.
Some prior art binding system required a two-stage operation. At a first stage, the binding element was held to permit loading of the sheets onto an open binding element. The open binding element with the inserted sheets were then moved to a second stage wherein a closing operation resulted in closing the binding element. An advantage of the present invention is to provide a binding apparatus which, in one stage, facilitates both: (a) the loading of sheets onto ringlets of a binder; and (b) the closing of the binder. This one-stage operation avoids a need to move the binder between loading and closing steps, greatly improving convenience to the user. More specifically, the binding apparatus of the invention is operable to hold the binder in one held position for both loading and closing the binder
An additional advantage of the present invention is the provision of a binding apparatus that properly orients a wire binder element between opposing and perpendicular former bars prior to squeezing the binder closed.
Another advantage of the present invention is the provision of a binding apparatus that maintains the proper orientation of the wire binder element during the closing operation wherein the binder element is bent closed.
A further advantage of the present invention is the provision of a binding apparatus that guides ends of the wire ringlets during a closure of the wire binder.
Yet another advantage of the present invention is the provision of a binding apparatus that is fully adjustable to accommodate different sizes of wire binders, but which is simple, reliable and requires few parts.
Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the presently preferred embodiments, the drawings and the claims.